Nonwoven fabrics have become quite popular for many different uses wherein textile-like properties, such as softness, drapability, strength and abrasion resistance are desired. One type of elastic nonwoven fabric is disclosed in U.S. Pat. No. 3,687,754 issued to Robert J. Stumpf on Aug. 19, 1971. Stumpf discloses a method of making a fabric by first forming a base web of thermoplastic fibers and then applying adhesive in an open pattern to one side of the web. The adhesive is allowed to set and cure. The web is then blade creped at an elevated temperature. The elevated temperature is sufficient to cause the open pattern of adhesive in which the fibers are embedded to be reactivated so that, during the creping step, the adhesive pattern is partially consolidated into a backing layer, while portions of the fibers across the open spaces of the adhesive pattern loop outwardly from the backing layer. The elevated temperature is controlled to minimize the bonding in the partially consolidated adhesive backing while at the same time allowing the thermoplastic fibers to be heat set to retain the crepe.
The type of creping, described in the Stumpf patent, wherein the web is adhered to a creping surface and removed therefrom by means of a doctor blade is generally known in the art as blade creping. The type of creping apparatus utilized in this invention, wherein the creping is accomplished through a combination of retarding and compressing the web during its travel on and removal from a roll, is known in the art as microcreping. U.S. Pat. No. 4,090,385, issued to Thomas D. Packard, on May 23, 1978, discloses a microcreping apparatus in which the roll is grooved. Although the creping apparatus described by Packard includes a grooved roll, it is contemplated by Packard that the grooves do not substantially contribute to the final shape of the creped web. Thus, at column 1, lines 64-68, Packard states that it is an object of his invention to provide a creping apparatus that has a minimum of undesirable effects such as longitudinal corrugation or streaking of the material caused by the retarder member. Packard, at column 2, lines 42-48, also states that the width of the grooves are quite small so that there is less tendency for the material to indent into and be corrugated or marked by the narrow grooves. And finally, at column 5, lines 46-50, Packard states that the grooves of the roll surface and the slots of the retarder member do not, in most instances, longitudinally corrugate or streak the material, or otherwise impair the uniformity of treatment of the material by the creping apparatus.
U.S. Pat. No. 3,949,128, issued to Kurt W. Ostermeier on Apr. 6, 1976, discloses a method of making an elastic nonwoven fabric by first forming a web of continuous filament thermoplastic fibers, which is stablized by a pattern of spot bonds extending through the formed webs. The stabilized web is then heated, drawn and heat set. The drawn web is then microcreped, that is, the web is forced against the surface of a smooth, heated drum which transports the web between a flexible blade and a retarding member to cause foreshortening or creping of the web. The microcreped web is then passed through an oven in order to heat set the filaments in their microcreped condition. Because the microcreping was effected on a smooth surface roll, a cross section of the microcreped fabric taken in the cross machine direction of the web, will have a relatively uniform thickness.